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464 results on '"Jang, Jum Suk"'

35. Expediting hole transfer kinetics through surface state modulation of a Ru–FeOOH and FeNi(OH)x dual-layer cocatalyst coated Zr–Fe2O3 photoanode for boosting photoelectrochemical water splitting.

Author

Anushkkaran, Periyasamy, Chae, Weon-Sik, Ryu, Jungho, Choi, Sun Hee, and Jang, Jum Suk

Abstract

The potential of a hematite photoanode for photoelectrochemical (PEC) water oxidation is primarily constrained by its sluggish water oxidation kinetics due to severe charge recombination at recombination surface states (r-SS). Abundant r-SS are responsible for a Fermi level pinning effect, which causes a potential drop in the Helmholtz layer. Tuning surface states is crucial for improving charge transfer at the semiconductor–electrolyte interface (SEI). In this context, cocatalyst loading is a potential strategy for promoting charge transfer by modulating intermediate surface states (i-SS). Accordingly, Ru-incorporated FeOOH and microwave-assisted FeNi(OH)x dual-layer cocatalysts (DLCs) were coated on a Zr-doped Fe2O3 photoanode to investigate surface charge transfer kinetics at the SEI. The optimized Zr-HT/Ru–FeOOH/FNH photoelectrode achieved a photocurrent density of 2.27 mA cm−2 with a surface charge separation efficiency of 96.6% at 1.23 V vs. RHE. The DLC modulated the i-SS and facilitated hole transfer, leading to Fermi level de-pinning through passivation of r-SS. Moreover, cocatalyst loading increased the surface-active area, which enhanced the number of active sites available for charge transfer reactions. During PEC water splitting, the optimized Zr-HT/Ru–FeOOH/FNH photoanode generated 38.2 and 18.5 μmol h−1 of H2 and O2 gases, respectively. The approach of using dual-layer cocatalysts provides a new technique for stimulating and advancing the effectiveness of metal oxide photoanodes by tailoring surface states for PEC water oxidation. [ABSTRACT FROM AUTHOR]

Published
2024
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42. Hierarchical Zr-doped Fe2O3 photoanodes decorated with in situ Au nanoparticles via a surfactant-assisted one-step hydrothermal approach for efficient photoelectrochemical water splitting.

Author

Anushkkaran, Periyasamy, Mahadik, Mahadeo A., Chae, Weon-Sik, Lee, Hyun Hwi, Choi, Sun Hee, and Jang, Jum Suk

Abstract

Achieving highly effective catalytic activity in photoelectrochemical (PEC) water splitting has become a challenge in the fabrication of Fe2O3 photoanodes due to their poor electrical conductivity and surface charge recombination. This study outlines a one-step hydrothermal route for the design of surfactant-assisted in situ Au nanoparticle (NP)-integrated Zr-doped Fe2O3 photoanodes for PEC water splitting. A cetyltrimethylammonium bromide (CTAB) surfactant and Au-incorporated Zr-doped Fe2O3 photoanode achieved a photocurrent density of 2.30 mA cm−2 at 1.23 V vs. RHE (1.23 VRHE). CTAB promoted the adsorption of Au NPs on the Zr-FeOOH during the synthesis, while Au NPs accelerated the charge transfer kinetics. The loaded Au NPs enhanced the separation of photo-generated electron–hole pairs; as a consequence, Au NPs effectively shuttled the holes from the hematite to the photoelectrode/electrolyte interface, leading to improved photocatalytic activity. Further, the optimized Zr-HT/CTAB/Au photoanode exhibited an intrinsic solar-to-chemical conversion (ISTC) efficiency of 1.034%. Moreover, impressively, the deposition of a NiCo(OH)x cocatalyst enhanced the PEC performance to 2.72 mA cm−2 at 1.23 VRHE. This study presents a potentially fruitful strategy for simultaneous in situ decoration of a surfactant and Au NPs with photoanodes for PEC water splitting. [ABSTRACT FROM AUTHOR]

Published
2023
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